The purpose of this proposal is to provide proof-of-concept that a novel therapy that prevents complement activation could be effective in reducing ischemia reperfusion injury (IRI) in transplanted organs. Complement activation after IRI in transplanted organs is a well-known phenomenon that may be responsible for delayed graft function and the hastening of acute rejection. The proposed therapy to reduce IRI is based on novel fusogenic lipid vesicles (FLVs) that rapidly incorporate into cell membranes. Our FLVs allow the rapid display of protective exogenous proteins on the surface of endothelial cells. The goal of this proposal is to optimize the display of a modified complement blocking protein named vaccinia virus complement control protein (VCP) on the surface of endothelial cells, and show that it can reduce complement induced damage after cells are exposed to hypoxia and reoxygenation. We hypothesize that the VCP displayed on the surface of endothelial cells will bind complement fragments early in the complement cascade and prevent cell injury. To test this hypothesis, we will perform the following specific aims. In Aim I, the formulation and concentration of biotinylated lipid vesicles will be optimized for optimal biotin coverage of cells. Aim II will assess on the surface of endothelial cells the biotin binding capacity of the streptavidin domain on our recently developed streptavidin-VCP (SA-VCP) chimeric protein. Aim III will assess the ability of SA-VCP to inhibit complement derived damage, after hypoxia and reoxygenation, of endothelial cells. If this proposal is successful it will demonstrate the effectiveness of both our novel cell membrane biotinylation platform technology and our newly developed anti-complement chimeric protein. In a Phase II proposal, we plan to test our technology in a transplantation animal model. We believe that our technology will make it possible to rapidly modify the functional characteristics of endothelial cell membranes without the use of gene therapy. If SA-VCP ex-vivo therapy is highly effective in preventing complement activation after IRI this will be extremely valuable for organ transplantation. The economic implications of our technologies for clinical application are vast.